1. Field of the Invention
This invention relates to a hand tool, more particularly to a swingable handle for use to deliver increased torque to rotate a tool bit of a hand tool.
2. Description of the Related Art
Referring to FIG. 1, a conventional handle of a hand tool, such as that disclosed in U.S. Pat. No. 6,189,420, is shown to include a rear handle body 1 which is pivoted to a front handle body 2 by a pivot pin 4 that passes through holes 102, 202 in the front and rear handle bodies 2,1. Three retaining concavities 203 are formed in the front handle body 2 for receiving three spring-biased retainers 3, respectively. A hole 103 is formed in the rear handle body 1 such that one of the retainer 3 can be retained in the hole 103 for arresting the rotation of the front handle body 2 relative to the rear handle body 1. The retainer 3 which is retained in the hole 103 can be pressed inwardly to permit rotation of the front handle body 2. However, the operation of the retainer 3, which has a relatively small surface, is not comfortable for the user.
Referring to FIG. 2, another conventional handle of a hand tool is shown to include a rear handle body 1xe2x80x2 with a pivot hole 101xe2x80x2, and a front handle body 2xe2x80x2 with an elongate pivot hole 201xe2x80x2. A pivot pin 3xe2x80x2 passes through the pivot holes 101xe2x80x2, 201xe2x80x2 to connect pivotally the rear handle body 1xe2x80x2 to the front handle body 2xe2x80x2. The front and rear handle bodies 1xe2x80x2, 2xe2x80x2 have mating walls which are disposed to mate with each other and which respectively have a retaining protrusion 102xe2x80x2 and a retaining groove 202xe2x80x2 that engage each other to restrain the front handle body 2xe2x80x2 from movement relative to the rear handle body 1xe2x80x2. When the front handle body 2xe2x80x2 is pressed forward to disengage the protrusion 102xe2x80x2 from the groove 202xe2x80x2, the rear handle body 1xe2x80x2 can rotate relative to the front handle body 2xe2x80x2 to adjust torque for rotating a tool bit mounted on the front handle body 2xe2x80x2. However, no device is provided for retaining the rear handle body 1xe2x80x2 at an angle relative to the front handle body 2xe2x80x2. In addition, a clearance is formed between the mating walls in the angular position of the handle bodies 1xe2x80x2,2xe2x80x2, thereby exposing the user""s hand to the risk of injury.
The object of the present invention is to provide a swingable handle which can be operated conveniently and comfortably to swing a rear handle body relative to a front handle body, which can restrain firmly the rear handle body from rotation relative to the front handle body, and which has a simple and compact construction that can lead to a reduced packaging size.
According to this invention, the swingable handle includes a rear handle body which has a front end wall facing forward, a rear end wall that is disposed opposite to the front end wall in a longitudinal direction parallel to a rotation axis of a tool-bit, and an outer surrounding wall that is disposed between the front and rear end walls. The front end wall has an accommodating cavity which extends toward the rear end wall in the longitudinal direction and which is surrounded by the outer surrounding wall. The outer surrounding wall has an inner peripheral edge portion to define a guiding slot which extends inwardly and in a radial direction relative to the rotation axis to communicate with the accommodating cavity. A front handle body has a mount end portion which is adapted to connect with a tool shaft for holding the tool bit, and a coupling end portion opposite to the mount end portion in the longitudinal direction. The coupling end portion is pivoted to the front end wall about a pivot axis transverse to the rotation axis. The coupling end portion has a first mating wall which extends in a transverse direction parallel to the pivot axis, which confronts the front end wall, and which is distal to the mount end portion relative to the pivot axis. A coupling member is mounted in and is movable relative to the accommodating cavity in the longitudinal direction. The coupling member includes a second mating wall which extends in the transverse direction and which confronts and mates with the first mating wall such that when the front end wall is turned about the pivot axis, the second mating wall is moved angularly relative to the first mating wall. The coupling member further includes a shifted portion which is fitted in and which is movable relative to the guiding slot in the longitudinal direction such that the second mating wall is moved by the shifted portion away from the first mating wall. A biasing member is disposed to bias the second mating wall toward the first mating wall in the longitudinal direction. A retaining member is disposed between the first and second mating walls such that when the second mating wall is biased to move toward the first mating wall, the retaining member prevents the first mating wall from moving angularly relative to the second mating wall, and such that when the second mating wall is moved by the shifted portion away from the first mating wall against biasing action of the biasing member, the second mating wall is angularly movable relative to the first mating wall between an in-line position, where the mount end portion is in-line with the rear handle body, and an angular position, where the rear handle body forms an angle with the rotation axis.